Hard metal is widely used in a broad application range including cutting tools, mining tools and wear parts.
Hard metal products, such as cemented carbides and cermets, contain relatively expensive elements, and there is a strong need to recover scrap by recycling spent and unused hard metal products, both for environmental and cost reasons. There are several processes currently used to recycle hard metal products including, e.g., the zinc process and the cold stream process.
However, the hard metal often contains elements that make the recycled material unsuitable as raw material base for the manufacture of certain hard metal grades. Such elements may be for example titanium, tantalum and chromium. These elements are commonly used as property enhancing additions in a variety of cemented carbide grades. These elements are, however, for other grades unwanted or even detrimental to the properties. There exist methods for purifying the raw material, mostly of chemical nature, but these are time-consuming and costly, and often involve environmentally unfriendly process steps or chemicals.
EP 233 162 discloses a method for separating cemented carbide bodies making use of the driving force for re-distribution of a binder metal melt between hard metal bodies, in contact with or close to each other, having different mean grain size, grain size distribution, relative proportions and compositions of the hard constituent phases. There is however still a need to sort hard metal bodies with regards to the presence or absence of different elements in the hard metal.